File README.openSUSE of Package shorewall
WARNING ======== Some openSUSE packages include a service file for ease of the SuSEfirewall2 configuration and opening the necessary ports. You have to open the required ports yourself using the Shorewall configuration files. SuSEfirewall2 is integrated with Yast so configuration can be done via a GUI. This is not the case for Shorewall. Enabling Firewall in /etc/sysconfig/network/config or in individual ifcfg-xxx files is not enough. /etc/sysconfig/shorewall should be configured. As the shorewall web page states "Shorewall is not the easiest to use of the available iptables configuration tools but I believe that it is the most flexible and powerful. So if you are looking for a simple point-and-click set-and-forget Linux firewall solution that requires a minimum of networking knowledge, check out alternatives." Now that you are warned remember to have fun